Losartan

Question 1

What drug class is Losartan?

Answer 1

An angiotensin II receptor antagonist/ARB

Question 2

What are the common indications for Losartan?

Answer 2

• Hypertension
• Diabetic nephropathy
• Chronic heart failure where ACEi are unsuitable

Question 3

What is the mechanism of action of Losartan?

Answer 3

Antagonist to AT1 (and AT2) receptors. Prevents the action of angiotensin II

So no vasoconstriction, less aldosterone released

It’s more effective than ACEi at inhibiting Ang-II vasoconstriction as it directly targets AT1 receptors

Question 4

What are the important adverse drug reactions of Losartan?

Answer 4

• Hypotension
• Hyperkalaemia (if low aldosterone, then more K+ reabsorbed)
• Causes or worsens renal failure

Question 5

What are the important drug-drug interactions with Losartan?

Answer 5

• Drugs that lead to hyperkalaemia

* NSAIDs